Thank you a lot for this hint.
I'm dismissing before the current View Controller, then present the SFSafariViewController.
Using following Code does help me out! Try it! - I'm on ... in Xcode 11.3.1 (macOS 10.14.6) and iOS 13.3.
// Command...
DispatchQueue.main.async(execute: {
/// code goes here
})
// my solution...
DispatchQueue.main.async {
self.present(safariVC, animated: true, completion: nil)
}